Within the field of oral and maxillofacial surgery one of the most important phases in the handling of fractures is intermaxillary fixation (IMF), due to the fact that during this step, the patient's original occlusion is reestablished.
Historically, intermaxillary fixation systems have been based on the use of teeth as anchorage for interdental surgical wires such as Erich, Ivy or Kazanjian arch bars, which are used in procedures that require maxillary fracture reductions. Notwithstanding their functionality, these systems have a number of disadvantages for both patient and surgeon, being the health of the gums the main issue at hand after their prolonged use.
For the patient, these systems cause discomfort and ailments in cases when the injuries are reversible, and when irreversible, they can produce grave periodontal disease. For the surgeon, these fixation systems require the existence of intact teeth in order to perform the procedure, a situation that is often difficult when faced with severe fractures. Additionally, their troublesome wire-based installation represents a biological hazard.
During the last twenty years, a solution to these problems has been presented with the appearance of IMF bone screws that have allowed for a rapid intermaxillary fixation. These screws are placed through the gingival and into the bone, leaving a protruding head. A wire is then attached between two or more screw heads in order to secure the IMF.
This system, however, has disadvantages. For example, it does not provide sufficient stability to the fixation, producing posterior open bites. Additionally, bone fragments can be twisted upon tightening the wires, they cannot provide a tension band effect, and they cannot be used for fractures between teeth or when post treatment requires the use of elastic IMF. Furthermore, their installation is difficult in complex traumas.
Most recently, a hybrid system has appeared on the market that utilizes both the utility of an arch bar as an IMF device, and the fixation of this bar using IMF self-tapping bone screws to connect it to the maxillary and mandibular arch. This device does provide for modular placement of the IMF bone screws, but carries the same disadvantages of the arch bar and bone screws of the prior art systems. The system has a plurality of hooks that sustain a wire or elastic, an arch bar that is laid upon the gums (making cleanliness difficult), and the placement of IMF self-tapping bone screws between the roots of teeth (potentially causing root and nerve damage).
Within the field of orthodontics, there are cases in which teeth may not be used as an anchorage point. In these cases, it is necessary to use bone anchorage in order to perform dental movements. Bone fixation systems in orthodontics have been historically based on the use of mini implants or screws with different devices on their heads, such as perforations allowed for the use of wires or elastic bands. More recently, some commercial brands have started implementing bone fixation systems made up of mini plates that are fixed to the bone. Notwithstanding their functionality, these systems have a number of disadvantages for both patient and surgeon. In the case of the traditional screw mechanism, their placement is the most inconvenient due to the location of the tooth apex. Regarding the mini plates systems, their biggest surgical difficulty lies in the difficulty of their insertion.
For the patient, these systems can damage the dental roots due to their proximity to the screws. For the surgeon, the biggest inconvenience is the high level of difficulty of locating the screws in possible and limited spaces without altering the anatomy and physiology of the bone and the tooth.
In all of these cases, the use of a less invasive system can avoid these inconveniences.